Tension control mechanism



Oct. 12, 1943. T. N. CARTER 2,331,765-

TENSION CONTROL MECHANISM Filed July 29, 1942 '7 Sheets-Sheet l IN V EN TOR.

mamas ffl'ar/zr BY W HTTOIP/VE) Oct. 12, 1943. ARTER 2,331,765

TENS ION CONTROL MECHANISM Filed July 29, 1942 7 Sheets-Sheet 2 T [W In I INVENTOR. T/mm: 1V larfer ,4 TTOPNEV Gd 12, 1943. N, CARTER TENSION CONTROL MECHANISM 7 Sheets-Sheet 5 Filed July 29, 1942 INVENTOR. Thomas M t'arfer film Oct. 12, 1943. N, CARTER TENSION CONTROL MECHANISM Filed July 29, 1942 '7 Sheets-Sheet 4 INVENTOR. fiomas M (drier BY Filed July 29, 1942 7 Sheets-Sheet 5 w l I m1 I i m m N\\ I\\\ 44/ I TI m N I I 5 a M m Y B Oct. 12, 1943. T. N. CARTER TENSION CONTROL MECHANiSM Filed July 29, 1942 '7 Sheets-Sheet 6 INVENTOR. Tia/flap jftarlez Get. 12, 1943. CARTER TENSION CONTROL MECHANISM Filed July 29, 1942 7 Sheets-Sheet 7 INVENTOR. mamas M'arier ITTORNEY Patented Oct. 12, 1943 UNITED STATES PATENT OFFICE,

TENSION CON TROL MECHANISM Thomas N. Carter, Milwaukee, Wis., assignor to Cameron Machine Company, Brooklyn, N. Y., a corporation of New York Application July 29, 1942, Serial No. 452,741

v what is commercially known as the Horton 7 Claims.

The present invention relates to machines employing tension control for a tensioned running web of flexible material. In machines of this character, such as winding machines and unwinding mechanism, a variable speed-control device is subjected to a progressively varying load and the effectiveness of said speed-control device is progressively varied in order to maintain a substantially constant tension on the web.

The main object and feature of this invention is to provide means whereby a constant tension on the web can be maintained or whereby, if desired, the effectiveness of the speed-control device can be varied disproportionately to the variation in load in a predetermined manner.

In the accompanying drawings the invention is disclosed in several concrete and preferred forms in which:

Fig. 1 is a view in side elevation of a centerwind winding machine embodying one form of the invention; 4

Fig. 2 is a fragmentary view looking in the direction of arrow 2 of Fig. 1;

Fig, 3 is a horizontal sectional view substantially on the plane of irregular line 3-3 of Fig. 1;

Figs. 4, 5 and 6 are diagrammatic views showing how different tensions or a uniform tension on the web can be obtained;

Fig. '7 is a view in side elevation of a modified form of the invention applied to a center-wind winding machine;

Fig. 8 is a view looking in the direction of I Fig. 13 is a view in side elevation of a still further modified form of the invention applied to a winding machine; and

Fig. 14 is a view similar to Fig. 13 but showing that form of the invention applied to unwinding mechanism.

Considering first the form of the invention shown in Figs. 1 to 6 inclusive, which form shows a center-wind winding machine, I indicates the winding shaft driven by suitable gearing 2 from a variable speed-control device 3. Device 3 is here in the form of a variable slip-friction drive or clutch, which can be of any type, but is here variable speed pulley, the effectiveness of which drive or clutch is varied by means of a clutchrod 4 in a well-understood manner.

The running web of flexible material is indicated at 5 and can come from any suitable source of supply such as a mill-roll stand (not shown). Web 5, before passing to winding shaft I, is trained around guide rollers 6 and 1, between which is located a tension control roll 8 that engages a bight 9 in the running web. Roll 8 is mounted on a carriage, here consisting of shaft 10 movable in a slot or guide I l of the framework. Shaft IU of the carriage is connectedto clutchcontrol rod 4 by any suitable means such as yoke l2, loosely surrounding said shaft, which yoke is pivotally connected to the end of a lever ll, pivoted at 14 on the framework, to which lever l3 clutch-rod 4 is pivotally connected at l5. Roll 8 is loosely mounted on shaft It so as to spin freely in response to the flow of the running web. Shaft l0 carries feat thereon a pinion i6 that mesheswith a stationary rack II. The arrangement is in duplicate. one at each end of shaft It, as will be understood, but-only one pinion and one rack is shown. Mounted fast on and rotatable with shaft I0 is a sheave l8. i8 is a flexible connection, having one end 20 anchored on said sheave, and trained therearound. 2| is a weight carried on the free end of the flexible connection.

It will now be understood that, when the wind ing operation is initiated, winding shaft i should rotate at high speed because the diameter of wound material M is practically the same as the diameter of said shaft and therefore each rotation of the shaft takes up only a short length of web. As the winding continues, the wound material, as it accumulates on shaft I, increases greatly in diameter so that, with each rotation of said shaft, an increasingly greater length of web materia1 is taken up and therefore th speed of shaft i should be slowed down. It will be understood, however, that the speed-control device, slip-friction drive or clutch 3 is subjected to a very light load at the beginning of the winding operation, and that this load varies or increases progressively as the wound material accumulates on shaft 1. Therefore, the clutch-faces of slipfriction drive 3 are pressed together only slightly at the beginning of the winding operation and there is very little, if any, slippage. As the load on shaft l increases, the clutch-faces of the slipfriction drive are pressed mor strongly together to furnish more power and the slippage increases.

Carriage or shaft l, which is capable of a movement of traverse by rolling in slot II and by the intermeshing of pinions I6 with racks I1, is subjected to the opposing forces of the tensioned web acting against roll 8, which urges the carriage in one direction, and of weight 2| which tends to urge it in the other direction. The resultant of these opposing forces is transmitted from carriage or shaft ||l through connections l2 and I3 and clutch-rod 4 to slip-friction drive 3 to thereby vary its effectiveness. As previously indicated, slip-friction drive 3 imparts, at the beginning of the windin operation, a relatively small amount of power to the winding shaft. As the load on the winding shaft increases, the slip-friction drive is unable, without. adjustment, to supply adequate power to said shaft and, consequently, the web slackens, or its tension relaxes. This slack is immediately taken up by a rolling movement of carriage l in slot under compulsion of weight 2|, and this movement is transferred through the connections described and clutch-rod 4 to the variable speedcontrol or slip-friction device 3 to thereby increase its effectiveness so as to supply more power to winding shaft I. This action continues during the winding operation and cause carriage ID to traverse slot II. It is not intended by the foregoing to give the impression that the traverse movement of carriage I0 is uninterruptedly in one direction; the tension in the web may become too great and therefore, under the influence of said web acting against roll 8, carriag I0 may temporarily move backwards to lessen the effectiveness of slip-friction drive 3. Nonetheless, during the winding operation, carriage ||l will move from adjacent one end of slot II to a position nearer the other end thereof.

It has been found that, in winding flexible material such as paper on a shaft, there is a tendency, in spite of efforts to maintain constant tension, to wind the outer convolutions of the wound material under greater tension than the core, sometimes to such an extent that the core is unable to support the roll, with the result that said core is telescoped out of the roll. Sometimes, in winding an extremely soft roll, even if constant tension on the web is substantially maintained, the inner convolutions do not have sufficient body to support the outer convolutions. To

. correct this condition, it is desirable, with certain materials and under certain conditions, to wind the roll progressively softer. To accomplish this, it is proposed to provide means to progressively vary the effectiveness of the speed-control device disproportionately to the variation in load thereon. That is to say, in the case of slipfriction drive 3, on which the load increases as wound material accumulates on the winding shaft, the increase in its effectiveness should be somewhat less than the increase in load. Attention is now directed to sheave l8. As shown in Figs. 1, 3 and 4, this sheave has, in the present instance, the form of a snail-like cam. Flexible connection I9 is attached to or anchored on the cam-sheave at the point 20, which is the point of smallest diameter of said cam-sheave, and is wound helically over the cam surface 200 of the sheave to the point of its greatest diameter, from which point the free end of said flexible connection depends and supports weight 2|. In Fig. 4, three positions in the traverse of carriage l0 during the winding operation are indicated at .17, y and 2. Position 3: shows the relation of the parts at the beginning of the winding operation,

from which it will be seen that weight 2| exerts its maximum power, being suspended from the point of greatest diameter of the cam-sheave. As the winding of the material on shaft I continues, and carriage l0 moves forward in slot flexible connection |9 will be unwound to a certain extent, as indicated at position 1 and Weight 2| will exert less power than previously, being now suspended from a smaller diameter of the camsheave. If the winding operation continues, position z may eventually be reached, in which position weight 2| will be least effective as it is suspended from the smallest diameter of the camsheave. The result is that, at the beginning of the winding operation, carriage l0, carrying roll 8, is urged toward the web by weight 2| when the latter is most effective but that, as carriage l0 traverses slot II, the effectiveness of weight 2| becomes less and less, and this despite the fact that cam-sheave I8 is turned directly in proportion to the traverse of carriage l0. Consequently, by reason of the lessened effect of weight 2|, the effectiveness of slip-friction drive 3 is increased to a less extent than the increase in its load and the roll of material will be wound progressively softer. By giving cam-sheave N3 the required shape, the variation in effectiveness of slip-friction drive 3 can be very accurately predetermined.

If, for any reason, the opposite result is desired, i. e. a somewhat softer core and somewhat harder outer convolutions, the arrangement shown in Fig. 5 can be employed, in which event cam-sheave l8 can be reversed so that initially weight 2| will be least effective as at position a: and finally most effective at position 3.

' Summing up the preceding constructions and operations, it will be seen that means are provided in combination with said carriage and weight to predeterminably and progressively vary the effectiveness of the speed-control device (here a slip-friction drive) disproportionately to the progressive variation in load thereon, and that said means consist of a rotatable member (here sheave l8 and/or extension ll of shaft I0), and further consist of means (here pinion I6 and rack IT) to turn said sheave or rotatable member in direct proportion to the progressive travers of the carriage, and that, finally, there are connecting means (here cam surface 200 and flexible connection I9) between rotatable member H3 and weight 2| to progressively render the latter disproportionately effective as said rotatable member is turned proportionately to the progressive traverse of the carriage.

If it be desired to have substantially constant tension on the Web throughout the winding operation, the arrangement shown in.Fig. 6 can be used. As there shown, sheave |8a is circular, so that weight 2| will be equally effective in any position.

In Figs. 7 and 8 is shown a modified form of the invention. In this form of the invention, flexible connection |9b is anchored on a camsheave 3b, as previously, but passes thereafter over a guide roller 22 and a circular sheave 23, weight 2 |b being suspended from the free end of I91). The action here is the same as that previously described.

In'Fig. 9, the invention is shown applied to a variable speed control device, different from that shown in the previous figures, i. e. a variable brake mechanism. In this instance, a shaft la is the support for a roll of material M to be unwound. This shaft is provided with a variable brake 30 which can be of any suitable construction such, for instance, as is shown in U. S. Patent No. 2,082,633. 40 indicates the brake control rod pivotally connected to lever 13c, pivoted at I40, and in turn pivotally connected to yoke 20, loosely mounted on shaft or carriage lflc, adapted to traverse slot llc. Carried fast on shaft 100, is a cam-sheave 180 to which is anchored a flexible connection 190 that passes over guide roller 22c and circular sheave 230, a weight 2l'c being attached to the end of the flexible connection. It will be understood that the condition in an unwinding mechanism is the reverse of that prevailing in a winding machine. That is to say: in the unwinding mechanism the diameter of the material M and the load is greatest at the beginning of the operation and decreases as the material is unwound. Consequently, the brake should be applied most strongly at the beginning of the operation so that shaft lc will rotate slowly, and should gradually be released as the unwinding proceeds and carriage llic traverses slot Ho. The arrangement of camsheave l8c is such that weight 2 la is most eflective at the beginning of the unwinding operation and less effective as the unwinding proceeds but, owing to the shape of the cam-sheave, the web will unwind under a constantly lessening tension so that said web will be wound on winding machine, indicated diagrammatically at W, with a hard core and softer outer convolutions.

In the examples of the invention thus far given, the cam-sheave has been shown as being mounted directly on carriage or shaft it or It with an exponent. This is not necessary. It is only necessary that said cam-sheave rotate in direct proportion to the traverse of carriage Hi. In Figs. 10 and 11 is shown a modified form of the invention in which cam-sheave l8d is mounted on a shaft 30 rotated in direct proportion to the traverse of carriage Hid in slot l Id by means of flexible member 3! connected at one end to yoke 12d of carriage lfld, passing overguide 32 and anchored at 33 on member 34 of shaft 38. Cam-sheave [8:1 is mounted fast on shaft 30, and has a flexible connection lSd anchored thereon to support a weight 2Id.

In Fig. 12 is shown an assemblage in which the tension control means are used both on the unwinding mechanism and the winding machine. As there shown, A indicates the unwinding mechanism constructed in accordance with the disclosure of Fig. Q and B is a winding machine constructed according to the disclosure of Figs. 1 to 3 inclusive. C is a processing mechanism, such as a printing machine, that acts on the web in passing from A to B. It will be seen that the tension of the web is controlled independently on opposite sides of C.

In Fig. 13, which shows a winding machine, carriage or shaft lUe, instead of controlling a flexible connection, carries an arm 35 that turns in proportion to the rolling movement of said shaft llle, and carries at its outer end an adjust-- able weight 36. Shaft lfie controls rod 4e of the slip-friction device in a manner like that previously described. At the beginning of the winding operation, said arm 85 may stand in a hori== zontal position where weight 38 will be most effective but, as carriage liie advances, said arm 35 is turned in an upward direction, thereby ren-= dering weight 36 less and less eflective as it approaches the vertical.

In Fig. 14, which shows an unwinding mechanism, carriage or shaft i carries an arm 3?,

that turns in proportion to the rollingmovement oi. said shaft NV, and carries at its end an ad- Justable weight 38. Shaft HI controls rod a of the brake mechanism in a 'manner'like that previously described. At the beginning of the unwinding operation said arm 3'! may stand in a horizontal position where weight it will be most effective but, as carriage lily advances, said am 3! is turned in an upward direction, thereby rendering weight 38 less and less efiect'ive as it approache the vertical.

It will thus be observed that in Figs. 1 to 12, the connecting means between the rotatable member and the weight include flexible connections, whereas in Figs. 13 and 14 said connecting means consist of arms 35 and 31.

I claim:

1. In a winding machine for a running web of flexible material in which the winding shaft is driven through a variable slip-friction drive the load on which progressively increasesas wound material accumulates on said winding shaft, and in which the eifectiveness of said .s'lip' -fri'ction drive is progressively varied by the traverse carriage having a roll that engages a bight in said running web, and in which the traverse of the carriage is controlled by the opposing forces exerted, by said web under tension and bya'weight, means to progressively vary the eifectiveness'of" the slip-friction drive as said load progressively increases, including: a rotatable sheave; means to turn said sheave in proportion tot hetraverse of the carriage, a flexible connection anchored at one end on said sheave and wound therearound, and a weight on the free end of said flexible connection. i

2. In a machine employing tension control' for a tensioned runnin web of flexible material, in which machine -a variable speed-control device is subjected to a progressive variation in load and in which the efiectiveness' of said speed-.

control device is progressively varied by the traverse of a carriage having aroll" that-engages a bight in said running web, andin whichthe traverse of the'carri age is controlled by the opposing forces exerted by'said web under tension and by a weight, means to predeterminably and progressively vary the effectiveness of the speedcontrol device disproportionately to said varia=- tion in load, including: a rotatable cam-sheave, means to turn said cam-sheave in direct propor tion to the traverse of said carriage, a flexible connection anchored at one end on said cam sheave and trained thereover, and a weight on the free end of said flexible connection.

3. In a winding machine for a running web of flexible material in which the winding shaft is driven through a variable slip-friction drive the load on which progressively increases as wound material accumulates on said winding shaft, and in which the efiectiveness of said slip-friction drive is progressively varied by the traverse of a carriage having a roll that engages a bight in said runing web, and in which the traverse of the carriage is controlled by the opposing forces ca erted by said web under tension and by a weight, means to predeterminably and progressively vary the effectiveness of the slip-friction drive proportionately to said increase in load, includ ing: a rotatable cam-sheave, means to turn said cam-sheave in direct proportion to the traverse of said carriage, a flexible connection anchored at one end on said cam-=sheave and trained thereover, and a weight on the free end of said flexible connection. e

4. In unwinding mechanism for a web of flexible material in which the shaft that supports the unwinding tensioned web is controlled by a variable brake the load on which progressively decreases as the web is unwound, and in which the effectiveness of said brake is progressively varied by the traverse of a carriage having a roll that engag. a bight in the tensioned running web unwound from said shaft, and in which the traverse of the carriage is controlled by the opposing forces exerted by said web under tension and by a weight, means to predeterminably and progressively vary the eifectiveness of the brake disproportionately to said decrease in load including: a rotatable cam-sheave, means to turn said cam-sheave in direct proportion to the traverse of said carriage, a flexible connection anchored at one end on said cam-sheave and trained thereovu', and a weight on the free end of said flexible connection.

5. In a machine employing tension control for a tensioned running web of flexible material, in which machine a variable speed-control device is subjected to a progressively varying load and in which the effectiveness of said speed-control device is progressively varied by the traverse of a carriage having a roll that engages a bight in said running web, and in which the traverse of the carriage is controlled by the opposing forces exerted by said web under tension and by a weight, means to predeterminably and progressively vary the effectiveness of the speed-control device disproportionately to said progressive variation in load, including, in combination with said weight and said carriage, a rotatable member, means to turn said rotatable member in direct proportion to the progressive traverse of said carriage, and connecting means between said rotatable member and said weight to progressively render the latter disproportionately efl'ective as the rotatable member is turned proportionately to the progressive traverse of said carriage.

6. In a winding machine for a running web of flexible material in which a winding shaft is driven through a variable slip-friction drive the load on which progressively increases as wound material accumulates on said winding shaft, and in which the efiectiveness of said slip-friction drive is progressively varied bythe progressive traverse of a carriage having a roll that engages a bight in said running web, and in which the progressive traverse of the carriage is controlled by the opposing forces exerted by said web under tension and by a weight, means to predeterminably and progressively vary the effectiveness of the slip-friction drive disproportionately to said increase in load, including, in combination with said weight and said carriage, a rotatable member, means to turn said' rotatable member in direct proportion to the progressive traverse of said carriage, and connecting means between said rotatable member and said weight to progressively render the latter disproportionately effective as the rotatable member is turned proportionately to the progressive traverse of said carriage.

7. In unwinding mechanism for a running web of flexible material in which the shaft that supports the unwinding web is controlled by a variable brake the load on which progressively decreases as the web is unwound, and in which the eflectiveness of said brake is progressively varied by the progressive traverse of a carriage having a roll that engages a bight in the running web unwound from saidshaft, and in which the progressive traverse of the carriage is controlled by the opposing forces exerted by said web under tension and by a weight, means to predeterminably and progressively vary the efiectiveness of the brake disproportionately to said decrease in load, including, in combination with said weight and said carriage, a rotatable member, means to turn said member in direct proportion to the progressive traverse of said carriage, and connecting means between said rotatable member and said weight to-progressively render the latter disproportionately effective as the rotatable member is turned proportionately to the progressive traverse of said carriage.

' THOMAS N. CARTER. 

